Pivoting pin joints for loader linkages and the like are normally lubricated with either grease or oil. Oil lubricated joints are typically preferred because they afford greater load carrying capacity and component life than grease lubricated joints, and they eliminate the routine maintenance needed to grease the joints on a daily or per shift basis. For this reason, oil lubricated joints are commonly referred to as low maintenance or maintenance free joints. However, such maintenance free joints must have an effective sealing system to prevent the loss of lubricating oil from the joint that would otherwise result in joint failure. Reference for instance, Reinsma et al. U.S. Pat. No. 4,961,667 issued Oct. 9, 1990 to Caterpillar Inc., which discloses a pivot joint for loader linkages and the like. This joint utilizes shear loaded face seals located in annular grooves of one of the members joined by the joint, the face seals including a sealing ring having a generally L-shaped cross-section, and an annular load ring. The load ring applies a force against the sealing ring which urges it into dynamic sealing engagement against another member connected by the joint. However, sometimes the members joined together by the joint are moved one relative to the other, such as when a heavy load is lifted or dumped, or a hard object is contacted, so as to exert a high pressure or spike against the face seal, causing the seal to be urged harder against the other member resulting in increased frictional wear and possible leakage so as to shorten the service life of the seal.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.